Treat SEALED_SUBCLASS_FQ_NAME_LIST change as a class signature change

#KT-19580

Original commit: 6354d9d54f

jps/jps-plugin/testData/comparison/classSignatureChange/nestedClassSignatureChanged/new.kt

@@ -0,0 +1,7 @@
+package test
+
+open class Base {
+    class Nested1 {
+        class Nested2
+    }
+}